Spring clutch



March 7, 1967 E. R. CONLON 3,307,668

SPRING CLUTCH Original Filed se t. 4; 1964 T .z izj 22 INVENTOR EDWARD RCONLON BY 12 m fia/Lwz, Joli/1W ZM ATTORNEY S United States Patent M3,307,668 SPRING CLUTCH Edward R. Conlon, Bristol, Conn., assignor toAssociated Spring Corporation, Bristol, Conn., a corporation of DelawareOriginal application Sept. 4, 1964, Ser. No. 394,403. Divided and thisapplication Aug. 5, 1966, Ser. No. 579,451

4 Claims. (Cl. 192-96) This application is a division of my co-pendingapplication Serial -No. 394,403, filed September 4, 1964, for springclutch.

This invention relates broadly to power transmitting clutches and, moreparticularly, to those of the type in which a helical spring isassociated in co-axial relation with the aligned ends of a drive shaftand an output shaft and may be operated to drivingly connect ordisconnect the shafts by being moved radially into and out of frictionalengagement with one or both of them.

The principal object of this invention has been to provide a springclutch of the described type but having a novel construction and mode ofoperation, by reason of which the clutch has fewer parts than knownclutch devices of the same type, has improved efliciency and otheroperating characteristics, and in which very simple actuating means areprovided for changing the diameter of the spring to operate it into andout of driving relation to one or both of the shafts.

The invention is described in the following specification and isillustrated in the accompanying drawings, in which:

FIG. 1 is a part sectional and part elevational view showing drive anddriven shafts and a spring clutch according to the invention;

FIG. 2 is a cross sectional view of the clutch shown in FIG. 1, taken online 2-2 of FIG. 1, and

FIGS. 3 and 4 are views similar to FIG. 1 showing two other embodimentsof the invention.

In the forms of the invention described in my copending application theclutch spring surrounds the ends of the drive and driven shafts and, inthe operation of the clutch, is radially contracted or expanded into orout of engagement with one or both of the shafts in the operation of theclutch, However, this surrounding relation of the spring to the shaftsis not a necessary relation of the parts in accordance with my inventionand, if desired, the clutch spring may be positioned within the alignedends of the drive and driven shafts and expanded into engagement withone or both of them to effect a driving connection. One embodiment ofthis form of the invention is disclosed in FIG. 1 0f the drawings andcomprises the axially aligned, axially spaced end parts of driving anddriven shafts 2, 4 these end parts being axially bored as shown at 6, 8.A helical clutch spring is positioned within the two shaft bores withits opposite end parts positioned, respectively, in the two shaft bores,and in this form of the invention the spring has an outside diameterless than the inside diameter of the bore in each of the two shafts andtherefore is normally out of engagement with both shafts. The ends ofthe wire forming the slutch spring are turned radially inwardly formingtwo tangs 12, 14 and a cylindrical actuating member 16 is positionedwithin the spring and extends from end to 3,397,668 Patented Mar. 7,1967 end thereof and has a cam slot 18 in its outer surface, one part 20of which is straight and extends axially of the actuating member, and asecond part 22 of which extends at an angle to the first part. The tangsare received, respectively, in the two parts of the cam slot. Suitablemeans, which are indicated at 30, are provided for imparting axialmovement to the actuator and it will be apparent that such movement inthe direction of the arrow in FIG. 1 will cause relative circumferentialmovement of the tangs, causing the spring to expand radially throughoutits length int-o engagement with the inner surfaces of the two shaftbores, thus drivingly connecting the two shafts. Release of the drivingconnection may, of course, be' made by movement of the operator in thedirection opposite to that required to cause driving connection.

In the embodiment of the invention disclosed in FIG. 1 and describedabove, the driving and driven shafts are norm-ally disconnected and areconnected by operation of the actuator to cause the clutch spring to beexpanded int-o engagement with both of them. In a second em bodiment ofthe invention, which is disclosed in FIG. 3, the two shafts are normallyconnected by the clutch spring which, in this form of the invention, isnormally in tight engagement throughout its outer periphery with theinner surfaces of the two bores in the drive and driven shafts. In thisform of the invention, axial movement of the actuator in one direction,i.e. the direction of the arrow in FIG. 2, causes the ends of the springto be moved circumferentially with respect to each other in suchdirections as to cause the spring to contract and move out of engagementwith the two shafts, thereby disconnecting them. Shaft connection may,of course, be restored by movement of the actuator in the oppositedirection.

In a further form which the invention may take the clutch spring isnormally connected to one shaft and disconnected from the other, thisembodiment being illustrated in FIG. 4 of the drawings. The driving anddriven shafts are therefore normally disconnected and may be connectedby movement of the actuator in one direction, i.e. the direction of thearrow in FIG. 4, and disconnected by movement of the actuator in theother direction, driving connection being made when both ends of theclutch spring are in engagement with the shafts.

While I have described and illustrated certain forms which my inventionmay take, it will be apparent to those skilled in the arts to which itrelates that other embodiments, as well as modifications of thosedisclosed, may be made and practiced with-out departing in any way fromthe spirit or scope of the invention, for the limits of which referencemust be made to the appended claims.

What is claimed is:

1. A clutch for connecting and disconnecting two aligned relativelyrotatable hollow ended shafts, comprising a helical coil springextending between the shafts and having its end parts within the hollowends of the shafts, an actuator positioned within the spring and beingmovable axially of the spring and shafts, said actuator having meansengaging the ends of the spring and operable on axial movement of theactuator to produce-relative circumferential movement of the spring endsthereby to change the radial dimension of at least part of the spring.

2. A clutch device according to claim 1, in which the outer periphery ofthe spring is normally spaced from the inner walls of both shafts.

3. A clutch device according to claim 1, in which the outer periphery ofthe spring normally engages the inner walls of both shafts.

4. A clutch device according to claim 1, in which the outer periphery ofthe spring normally engages the inner Wall of one shaft and is spacedfrom the inner wall of the other shaft.

References Cited by the Examiner UNITED STATES PATENTS Wahl.

Starkey 192-41 Dale et al l92-81 X Winchell 19281 X

1. A CLUTCH FOR CONNECTING AND DISCONNECTING TWO ALIGNED RELATIVELYROTATABLE HOLLOW ENDED SHAFTS, COMPRISING A HELICAL COIL SPRINGEXTENDING BETWEEN THE SHAFTS AND HAVING ITS END PARTS WITHIN THE HOLLOWENDS OF THE SHAFTS, AN ACTUATOR POSITIONED WITHIN THE SPRING AND BEINGMOVABLE AXIALLY OF THE SPRING AND SHAFTS, SAID ACTUATOR HAVING MEANSENGAGING THE ENDS OF THE SPRING AND OPERABLE ON AXIAL MOVEMENT OF THEACTUATOR TO PRODUCE RELATIVE CIR-